I think a lot of things balance out in the long term. If the yen ever goes to 120/$ again or more, then you'll feel like a genius, and be able to spend that money with glee. But yeah, looking at it at today's rate (107/$ according to Google), you feel like a roasted fool.

I think, like any sort of gambling, it helps to set a set-point. "OK, when the $ is at 105, I'm going to send X amount of yen." The $ might drop to 100 (or even 79, LOL) but you'll still be better off than certain setpoints.

If, on the other hand, you need those dollars to pay off dollar debts, it's good that you didn't mess around. Safety and security is worth a little bit of interest. Two million yen is a bit more than your average "emergency fund", but not by much. By having $15,000 of "safety money" in the bank, you are free to put your future earnings towards riskier investments.